Abstract:

Distributed node systems and methods provide emergency call services to
users indoors. A distributed node can be located in a building and
configured to receive call requests from users in the building. The
distributed node can transmit call requests to a central node that relays
the call requests to a wireless network. The distributed node can also
transmit node identifying information with the call request, which may be
relayed to the wireless network. The wireless network can determine that
a call request is a request for an emergency call and obtain location
information and emergency services provider routing information based on
a node identifier. The wireless network can transmit the location
information to the emergency services provider using the emergency
services provider routing information and set up the requested call.

Claims:

1. A system for providing emergency call services to indoor areas, the
system comprising:a wireless network device configured to:receive a first
call request indicative of a call request received from a wireless device
at a distributed node, transmitted from the distributed node to a central
node, and transmitted from the central node to the wireless network
device; anddetermine that the first call request is an emergency call
request, obtain location information based on the first call request,
transmit the location information to an emergency services provider, and
set up a call based on the first call request.

2. The system of claim 1, wherein the first call request is further
indicative of a node identifier transmitted from the distributed node to
the central node, and transmitted from the central node to the wireless
network device.

3. The system of claim 1, wherein the first call request comprises a node
identifier.

4. The system of claim 3, wherein the wireless network device is further
configured to transmit the node identifier to a location services device
and receive the location information from the location services device.

5. The system of claim 3, wherein the wireless network device is further
configured to obtain emergency services provider routing information.

7. The system of claim 1, wherein the wireless network device configured
to determine that the first call request is the emergency call request
comprises the wireless network configured to determine that the first
call request is the emergency call request based on a destination number
of the first call request.

8. A method of providing emergency call services to indoor areas
comprising:receiving on a distributed node a call request from a wireless
device and transmitting the call request to a central node;receiving the
call request on the central node and transmitting the call request to a
wireless network;receiving the call request on the wireless network,
determining that the call request is an emergency call request, and,
responsive to determining that the call request is the emergency call
request, obtaining location information based on the call request;
andtransmitting the location information to an emergency services
provider and setting up a call based on the call request.

9. The method of claim 8, wherein transmitting the call request to the
central node comprises transmitting a node identifier and the call
request to the central node, andwherein receiving the call request on the
central node and transmitting the call request to the wireless network
comprises receiving the call request and the node identifier on the
central node and transmitting the call request and the node identifier to
the wireless network.

10. The method of claim 9, wherein obtaining location information based on
the call request comprises transmitting the node identifier to a location
services device and receiving the location information from the location
services device.

12. The method of claim 8, wherein transmitting the call request to the
central node comprising determining the central node from among a
plurality of central nodes and, responsive to determining the central
node from among the plurality of central nodes, transmitting the call
request to the central node.

13. The method of claim 8, wherein transmitting the call request to the
central node comprises determining that a first central node is not
accessible and, responsive to determining that the first central node is
not accessible, transmitting the call request to an alternate node.

14. The method of claim 8, wherein transmitting the call request to the
central node comprises transmitting the call request to an intermediate
node; andreceiving the call request on the intermediate node and
transmitting the call request to the central node.

15. A computer-readable medium having stored thereon computer-executable
instructions implementing a method of providing emergency call services
to indoor areas, the method comprising:receiving on a distributed node a
call request from a wireless device and transmitting the call request to
a central node;receiving the call request on the central node and
transmitting the call request to a wireless network;receiving the call
request on the wireless network, determining that the call request is an
emergency call request, and, responsive to determining that the call
request is the emergency call request, obtaining location information
based on the call request; andtransmitting the location information to an
emergency services provider and setting up a call based on the call
request.

16. The medium of claim 15, wherein transmitting the call request to the
central node comprises transmitting the call request to an alternate
node, wherein the alternate node is configured to transmit the call
request to the central node.

17. The medium of claim 16, wherein transmitting the call request to the
alternate node comprises determining that the distributed node cannot
communicate directly with the central node and, responsive to determining
that the distributed node cannot communicate directly with the central
node, transmitting the call request to the alternate node.

18. The medium of claim 15, wherein transmitting the call request to the
central node comprises transmitting the call request to the central node
wirelessly.

19. The medium of claim 15, wherein transmitting the call request to the
central node comprises transmitting the call request to the central node
using a wired connection.

20. The medium of claim 15, wherein the central node is located in a first
building, the distributed node is located in a second building, and the
first building and the second building are geographically proximate.

Description:

TECHNICAL FIELD

[0001]The technical field generally relates to wireless communications and
more specifically relates to providing enhanced 911 service to indoor
locations.

BACKGROUND

[0002]Communications devices such as cellular telephones, mobile
communication devices, personal digital assistants (PDAs), laptops, and
the like are becoming more prevalent as technology advances and makes
these devices more powerful and more affordable. Location-based services
have been developed for these devices based on the premise that service
providers are able to identify the location of mobile devices attached to
their networks and provide additional services based on that location.
More specifically, it is a requirement of the Federal Communications
Commission (FCC) that emergency 911 (E911) calls made from mobile devices
must provide caller location accuracy within 50 meters for 67% of the
calls and within 100 meters for 100% of the calls for handset based
location determination. It is further required that E911 calls made from
mobile devices must provide caller location accuracy within 100 meters
for 67% of the calls and within 300 meters for 100% of the calls for
network based location determination. Most devices in use by typical
users do not have direct global positioning system (GPS) capabilities.
Some may use assisted GPS, where the network assists a properly
configured device with locating and communicating with GPS satellites in
order to obtain location information. Other devices may have no location
capabilities on-board, and the networks supporting such devices may
determine the device location using various methods known to those
skilled in the art, including trilateration.

[0003]Many of the technologies used to provide or determine location
information are less effective or not available indoors. This may be due
to the inability to communicate with GPS satellites. In other situations,
a newer technology, such as 3rd generation (3G) wireless technology,
may not be fully capable of providing location technology indoors and an
older technology, such as 2nd generation (2G) wireless technology
may be used to determine or acquire the location of a device. However,
this may involve installing and/or maintaining redundant network
equipment, for example installing and maintaining both 2G and 3G
equipment, resulting in great cost to a carrier or network provider in
order to comply with FCC requirements. Also, the coverage areas of an
older technology network may not exactly overlap the coverage area of the
newer technology network, leaving gaps in emergency coverage which may
result in a failure to meet FCC requirements, and, more importantly,
delayed or failed response to emergency calls.

SUMMARY

[0004]Methods and systems are disclosed for providing a distributed node
system that facilitates providing emergency call services to users
located indoors. A distributed node may be located in a building and
configured to receive call requests from users in the building. Location
information for the distributed node may be recorded by a wireless
network operator or a third party upon or before the activation of the
distributed node. The distributed node may transmit received call
requests to a central node that relays the call requests to a wireless
network. Along with the call request, the distributed node may also
transmit node the distributed node identification information, such as a
node identifier, with the call request. Alternatively, the distributed
node may alter the call request to include a node identifier.

[0005]The central node may transmit a received call request and node
identifier to a wireless network. The wireless network may determine that
the call request is a request for an emergency call and obtain location
information and emergency services provider routing information based on
the node identifier. The wireless network may obtain location information
and emergency services provider routing information by transmitting the
node identifier to a location services device and receiving the requested
information from the location services device. The wireless network may
transmit the location information received from the location service
device to the emergency services provider using the emergency services
provider routing information. The wireless network may also set up the
requested call between the requesting device and the emergency services
provider.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]The following detailed description of preferred embodiments is
better understood when read in conjunction with the appended drawings.
For the purposes of illustration, there is shown in the drawings
exemplary embodiments; however, the subject matter is not limited to the
specific elements and instrumentalities disclosed. In the drawings:

[0007]FIG. 1 is a graphical representation of an exemplary, non-limiting
network in which E911 services using distributed nodes may be
implemented.

[0009]FIG. 3 is a block diagram of a non-limiting, exemplary wireless
device that may be used in connection with an embodiment.

[0010]FIG. 4 is a block diagram of a non-limiting, exemplary processor in
which the present subject matter may be implemented.

[0011]FIG. 5 is an overall block diagram of an exemplary packet-based
mobile cellular network environment, such as a GPRS network, in which the
present subject matter may be implemented.

[0012]FIG. 6 illustrates a non-limiting, exemplary architecture of a
typical GPRS network as segmented into four groups.

[0013]FIG. 7 illustrates a non-limiting alternate block diagram of an
exemplary GSM/GPRS/IP multimedia network architecture in which the
present subject matter may be implemented.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0014]FIG. 1 illustrates an exemplary, non-limiting network and system
that may be used to implement E911 and/or other emergency call services
using distributed nodes. Network 101 may be any type of network capable
of providing wireless services to wireless devices of any type. Network
101 represents any number of interconnected networks that may be composed
of any number and type of wired and/or wireless network devices. Network
101 may provide wireless service to device within the area of campus 102.
Campus 102 may be any area where one or more buildings are arranged
proximate to one another in physical space. Alternatively, or
additionally, one or more of the buildings within campus 102 may be
geographically distant from one or more other buildings in campus 102,
but may be communicatively connected through various means, including
wireless and wired communication means.

[0015]The operator of network 101 may wish to provide wireless service to
campus 102 without providing the full scale base stations that may be
required to provide every portion of campus 102 with direct access to
network 101. For example, the operator of network 101 may wish to provide
3G network services across campus 102, but may find that implementing
base stations that communicate directly with network 101 using the
preferred technology every place where connectivity to network 101 is
desired (including inside buildings 121, 131, and 141) is cost
prohibitive. Therefore, in one embodiment, the operator of network 101
may install a distributed node environment on campus 102.

[0016]In such a configuration, a central node may be installed in a
central location. For example, central node 120 may be installed in
building 121. Central node 120 may communicate directly with network 101,
and may also communicate with distributed nodes located throughout campus
102. Central node 120 may be a fully functional and fully featured
wireless network base station that directly receives wireless
communications data from wireless devices and facilitates communication
between wireless devices and network 101. Central node 120 may also relay
information, including data, voice, and any other form of wired or
wireless communication, between distributed nodes 130 and 140 and network
101. Alternatively, central node 120 may be dedicated to serving only as
a central node or hub that relays data, such a voice call data, between
network 101 and distributed nodes 130 and 140. In such an embodiment,
central node 120 may not directly receive wireless or wired
communications from end user devices. Distributed nodes 130 and 140 may
be located respectively in buildings 131 and 141. Distributed nodes 130
and 140 may not be capable of communicating directly with network 101,
but may instead be configured to communicate directly with central node
120, and may not have all the features and functions of a full wireless
network base station. This may allow distributed nodes 130 and 140 to be
less expensive to manufacture and/or purchase because less equipment is
needed, and such nodes may also be less expensive to install and operate.
Distributed nodes 130 and 140 may communicate with central node 120 using
any effective means, including wired and wireless means. Note that each
of nodes 120, 130, and 140 may any type and any number of network devices
configured to allow communications between devices of any type. In one
example, any or all of nodes 120, 130, and 140 may be distributed node-B
wireless base stations.

[0017]Nodes such as central node 120 and distributed nodes 130 and 140 may
be located in an area of a building where emergency personnel are likely
to go. For example, such nodes may be located in the lobbies of
buildings. These nodes may also include other elements that are
distributed throughout a building in order to improve performance. For
example, repeaters, splitters, antennas, and/or similar devices may be
installed throughout a building so that adequate wireless coverage can be
provided throughout the building.

[0018]Gateway Mobile Location Center (GMLC) 111 may be communicatively
connected to and provide location services for network 101. When a
location of a wireless device is needed by network 101, for example when
an emergency call such as a 911 call is received on network 101, network
101 may request location information for the calling device from GMLC
111. Such location information may be for the node that received the
emergency call rather than for the calling device itself GMLC 111 may
determine location information by accessing a database and determining
location information from related data, such as a cell identifier. In
some embodiments, the cell identifier may be a Cell Global Identity
(CGI). A CGI may be a concatenation or combination of a Location Area
Identity (LAI) and a Cell Identity (CI) that uniquely identifies a
particular cell. The operator of network 101 may provide location
information and cell identifiers for each of nodes 120, 130, and 140 to
GMLC 111, which may statically store such information, for example, in a
database. This information may include longitude and latitude, an
address, and/or any other physical location information. This information
may be configured on GMLC 111 as each node is constructed or configured,
or may be set following construction or configuration of the nodes,
either before or after the nodes become active. Cell identifiers and/or
location information may be stored on GMLC 111 or may be stored on a
separate device or system that is accessible by GMLC 111. Any other
configuration of devices or systems that allow a GMLC access to location
information for nodes and/or cells is contemplated as within the scope of
the present disclosure.

[0019]For each location record stored or accessible by GMLC 111, GMLC 111
may also store or otherwise have access to public safety answering point
(PSAP) data, such as routing data. This information may be used by
network 101 to direct an incoming call to the correct destination. For
example, if an emergency call is received on network 101, and network 101
transmits a location query to GMLC 111, GMLC 111 may respond with the
location information for the base station that initially received the
emergency call and the destination phone number or other destination data
for the 911 call center nearest to or assigned to the base station. This
allows network 101 to direct the call to the appropriate emergency
services center or PSAP based on the location of the base station. In one
embodiment, the appropriate emergency services center or PSAP may be the
emergency services center or PSAP nearest to or otherwise assigned to the
base station.

[0020]When nodes 120, 130, and 140 are installed, configured, activated,
or otherwise prepared for use, the operator of network 101 may provide
location information for each such nodes to GMLC 111. This location
information may be phase two location information as known by those
skilled in the art, which includes longitude and latitude, and/or an
address of the building in which each node is installed. Such location
information may be used to facilitate emergency calls initiated by users
in buildings on campus 102. For example, if user 150 is operating
wireless device 151 inside building 131 and initiates a call to 911, the
call request may be received at distributed node 130. Distributed node
130 may transmit the call request to central node 120 located in building
121. In transmitting the call request, distributed node 130 may include a
cell identifier that uniquely identifies distributed node 130. Central
node 120 may relay the call request including the cell identifier to
network 101.

[0021]Upon receiving the call request, network 101 may evaluate the call
request and determine that this is a request for an emergency call, and
therefore network 101 will require location information to properly
process the request. Network 101 may then transmit a request for location
information and/or PSAP routing information to GMLC 111. Such a request
may contain the cell identifier or other data that may be used by GMLC
111 and/or other systems or devices to determine location information
and/or PSAP routing information. GMLC 111 may obtain location information
and PSAP routing information and transmit such to network 101 and/or PSAP
110. This information may include the physical address and/or longitude
and latitude of building 131, and may include routing information for
PSAP 110. Upon receipt of this information, network 101 may then set up a
call between wireless device 151 and PSAP 110, and may also transmit the
location information received from GMLC 111 to PSAP 110. Thus, an
accurate location for user 150 is provided to the appropriate emergency
services and help may be quickly provided to user 150.

[0022]In providing telecommunications services to wireless device 151,
data and voice communications, as well as any other form of
communications, may be relayed between distributed node 130 and network
101 by central node 120. Thus all traffic between wireless device 151 and
PSAP 110 may traverse network 101, central node 120, and distributed node
130. Alternatively, as will be discussed in more detail, other central
nodes may be used to relay traffic from wireless device 151 to PSAP 110,
from PSAP 110 to wireless device 151, or both.

[0023]Similarly, if user 160 is in building 141 and places an emergency
call using wireless device 161, distributed node 140 may send a call
request to central node 120, which may relay the call request and a cell
identifier to network 101. Network 101 may obtain location information
and PSAP routing data for distributed node 140 from GMLC 111, and use
such information to set up a call between wireless device 161 and PSAP
110, and provide location information for building 141 to PSAP 110.

[0024]In one embodiment, alternate nodes may be configured on campus 102
to provide redundancy or duplicate connectivity means. For example, in
the event of a major event, such as an explosion or release of poisonous
materials, many calls may be initiated that connect through the
distributed nodes of campus 102. In such an event, the volume of traffic
generated by such calls and call requests may overwhelm central node 120.
Alternatively, some event may render central node 120 inoperable. In
either scenario, an alternate central node, such as alternate node 170
configured in building 171, may be configured to perform the duties of a
central node. In one embodiment, alternate node 170 may not relay calls,
call requests, or other traffic between distributed nodes and network 101
unless central node 120 is incapable of handling such traffic. In such an
embodiment, alternate node 170 may serve as a back-up central node. In
another embodiment, alternate node 170 may share traffic relay functions
with central node 120 on a normal basis, and thus serve as a redundant
central node. Any other configuration of nodes is contemplated as within
the scope of the present disclosure.

[0025]In an embodiment with a configured alternate node 170, calls and
other traffic may be relayed directly from distributed nodes, such as
distributed node 140, to alternate node 170, which may relay such traffic
to network 101, and also relay traffic from network 101 to distributed
nodes so that the traffic reaches the end user devices. Alternatively,
when multiple nodes serve as central nodes, traffic may be relayed from a
distributed node, such as distributed node 140, to network 101 by central
node 120, and relayed from network 101 to distributed node 140 by
alternate node 170, or vice versa. Such asymmetric routing of traffic may
be desired sue to bandwidth or equipment limitations or configurations,
and all such routing and any variations thereof are contemplated as
within the scope of the present disclosure.

[0026]In another embodiment, distributed nodes may also serve to relay
traffic between other distributed nodes and one or more central nodes.
For example, if central node 120 is rendered inoperable for any reason,
distributed node 130 may be configured to determine that central node 120
is not available and, upon such a determination, may transmit traffic
intended for network 101 to an intermediate node that may then relay the
traffic to a central node. In one embodiment, distributed node 140 may
serve as an intermediate node. Distributed node 140 may be configured to
transmit such traffic to alternate node 170, which may relay the traffic
to network 101. Distributed node 140 may be configured to determine
whether central node 120 is available and may be configured to determine
for itself which node is the appropriate recipient for such traffic. For
example, if central node 120 is actually active, but the connection
between distributed node 130 and central node 120 is unavailable, then
distributed node 140 may pass the traffic from distributed node 130 to
central node 120. Alternatively, if distributed node 140 determines that
it cannot communication with central node 120, distributed node 140 may
pass the traffic from distributed node 130 to alternate node 170.

[0027]In some embodiments, intermediate nodes may be configured to only
provide traffic relay services between distributed nodes and central
nodes, while in other embodiments central, distributed, or any other type
of node may also provide intermediate node functions. In some
embodiments, the functions that each node serves in any given
configuration may be determined by the network and node resources that
are available at a given time. In other embodiments, nodes may have
static or fixed functions and may not be configured or capable of
performing other functions. In still other embodiments, nodes may be
configured to primarily perform certain functions and configured to
perform other functions only in the event of a node failure or other node
or network problem or unavailability, thus serving as backup nodes in the
event that one or more nodes become inoperable. Any other configuration
of nodes and any means of determining which nodes are suitable for
relaying traffic are contemplated as within the scope of the present
disclosure.

[0028]FIG. 2 illustrates an exemplary non-limiting method of implementing
the present subject matter. At block 210 a call request may be received
at a distributed node. This may be any distributed node as described
herein, such as distributed nodes 130 and 140, or a central node that may
perform the functions of a distributed node, such as central node 120 or
alternate node 170, or any other node, device, group of devices, or
system that is configured to perform the functions of a distributed node.
All such embodiments are contemplated.

[0029]At block 220, the call request may be transmitted to a central node.
The call request may be altered or modified by the distributed node to
include a cell identifier or other data that will indicate the identity
and/or location of the distributed node. This may be any central node as
described herein, such as central node 120 or alternate node 170, or any
other node, device, group of devices, or system that is configured to
perform the functions of a central node. Such a central node may also be
configured to perform the functions of a distributed node and/or other
functions. In one embodiment, the distributed node and the central node
described in reference to FIG. 2 may be the same node. In other
embodiments they are different nodes in the same physical location. In
still other embodiments they are physically separate nodes. All such
embodiments are contemplated.

[0030]At block 230, the central node may transmit the call request to a
network. This may be any type of network as described herein, including a
wireless network, and may be any other type of network capable of
performing the communications functions described herein.

[0031]At block 240, a determination is made as to whether the call request
is a request for an emergency call, such as a 911 call. This
determination may be made on a network device of a wireless network as
described herein. In other embodiment, the determination may be made on
another device, such as a central node or a distributed node. In such
embodiments, an indicator of the emergency status of the call request may
be concatenated onto, supplement, or otherwise be included in the call
request so that the indicator may be detected by the network receiving
the call request. The determination of whether the call request is an
emergency call request may be based on the recipient number (such as
"911") or on any other characteristic, data, or identifier contained
within the call request. All such embodiments are contemplated as within
the scope of the present disclosure.

[0032]If it is determined that the call request is not an emergency call
request, at block 250 the call request is processed as normal and the
requested call is set up or otherwise handled and the method is complete.

[0033]If it is determined that the call request is an emergency call
request, at block 260 location information and/or PSAP routing
information is obtained. This be accomplished using any of the means
disclosed herein, including transmitting a cell identifier or other
identifying data to a GMLC, such as GMLC 111, and receiving a response
providing the location information and/or the PSAP routing information.
The same device may perform the determination of emergency status of a
call request and determine the location and PSAP routing data in some
embodiments, while in other embodiments these functions may be performed
by two or more devices. All such embodiments are contemplated as within
the scope of the present disclosure.

[0034]At block 270, location data may be transmitted to the appropriate
PSAP, in one embodiment based on the obtained PSAP routing information.
The requested call may also be set up between the appropriate PSAP and
the user device that requested the emergency call. Any means and methods
of providing location data to a PSAP and connecting a call between a PSAP
and a user device are contemplated.

[0035]FIG. 3 illustrates an example wireless device 1010 that may be used
in connection with an embodiment. References will also be made to other
figures of the present disclosure as appropriate. For example, wireless
devices 151 and 161 may each be a wireless device of the type described
in regard to FIG. 3, and may have some, all, or none of the components
and modules described in regard to FIG. 3. It will be appreciated that
the components and modules of wireless device 1010 illustrated in FIG. 3
are illustrative, and that any number and type of components and/or
modules may be present in wireless device 1010. In addition, the
functions performed by any or all of the components and modules
illustrated in FIG. 3 may be performed by any number of physical
components. Thus, it is possible that in some embodiments the
functionality of more than one component and/or module illustrated in
FIG. 3 may be performed by any number or types of hardware and/or
software.

[0036]Processor 1021 may be any type of circuitry that performs operations
on behalf of wireless device 1010. In one embodiment, processor 1021
executes software (i.e., computer readable instructions stored in a
computer readable medium) that may include functionality related to
transmitting and receiving telephonic communications including emergency
calls of any type, communicating with, operating, or interfacing with
distributed and/or central nodes or running software configured to
operate, communicate, or interface with distributed and/or central nodes,
for example. User interface module 1022 may be any type or combination of
hardware and/or software that enables a user to operate and interact with
wireless device 1010, and, in one embodiment, to interact with a system
or software enabling the user to place, request, and/or receive emergency
calls, and/or a system or software enabling the user to view, modify, or
delete related software objects. For example, user interface module 1022
may include a display, physical and/or "soft" keys, voice recognition
software, microphone, speaker and the like. Wireless communication module
1023 may be any type or combination of hardware and/or software that
enables wireless device 1010 to communicate with wireless network
equipment, distributed nodes, and/or central nodes, for example, network
101, distributed node 130, distributed node 140, central node 120,
alternate node 170, or any other type of wireless communications network
or network equipment. Memory 1024 enables wireless device 1010 to store
information, such as emergency call numbers and preferences. Memory 1024
may take any form, such as internal random access memory (RAM), an SD
card, a microSD card and the like. Power supply 1025 may be a battery or
other type of power input (e.g., a charging cable that is connected to an
electrical outlet, etc.) that is capable of powering wireless device
1010. SIM 1026 may be any type Subscriber Identity Module and may be
configured on a removable or non-removable SIM card that allows wireless
device 1010 to store data on SIM 1026.

[0037]FIG. 4 is a block diagram of an example processor 1158 which may be
employed in any of the embodiments described herein, including as one or
more components of wireless devices 151 and 161, as one or more
components of network equipment, node equipment, or related equipment,
such as any component shown in FIG. 1, and/or as one or more components
of any third party system or subsystem that may implement any portion of
the subject matter described herein. It is emphasized that the block
diagram depicted in FIG. 4 is exemplary and not intended to imply a
specific implementation. Thus, the processor 1158 can be implemented in a
single processor or multiple processors. Multiple processors can be
distributed or centrally located. Multiple processors can communicate
wirelessly, via hard wire, or a combination thereof

[0039]The processor 1158 can be implemented as a client processor and/or a
server processor. In a basic configuration, the processor 1158 may
include at least one processing portion 1160 and memory portion 1162. The
memory portion 1162 can store any information utilized in conjunction
with transmitting, receiving, and/or processing emergency calls, other
telephonic communications, etc. For example, the memory portion is
capable of storing call preferences and/or software capable of processing
call requests, receiving calls, etc. Depending upon the exact
configuration and type of processor, the memory portion 1162 can be
volatile (such as RAM) 1166, non-volatile (such as ROM, flash memory,
etc.) 1168, or a combination thereof The processor 1158 can have
additional features/functionality. For example, the processor 1158 can
include additional storage (removable storage 1170 and/or non-removable
storage 1172) including, but not limited to, magnetic or optical disks,
tape, flash, smart cards or a combination thereof Computer storage media,
such as memory and storage elements 1162, 1170, 1172, 1166, and 1168,
include volatile and nonvolatile, removable and non-removable media
implemented in any method or technology for storage of information such
as computer readable instructions, data structures, program modules, or
other data. Computer storage media include, but are not limited to, RAM,
ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital
versatile disks (DVD) or other optical storage, magnetic cassettes,
magnetic tape, magnetic disk storage or other magnetic storage devices,
universal serial bus (USB) compatible memory, smart cards, or any other
medium which can be used to store the desired information and which can
be accessed by the processor 1158. Any such computer storage media may be
part of the processor 1158.

[0040]The processor 1158 can also contain the communications connection(s)
1180 that allow the processor 1158 to communicate with other devices, for
example through node and network equipment as illustrated in FIG. 1.
Communications connection(s) 1180 is an example of communication media.
Communication media typically embody computer-readable instructions, data
structures, program modules or other data in a modulated data signal such
as a carrier wave or other transport mechanism and includes any
information delivery media. The term "modulated data signal" means a
signal that has one or more of its characteristics set or changed in such
a manner as to encode information in the signal. By way of example, and
not limitation, communication media includes wired media such as a wired
network or direct-wired connection as might be used with a land line
telephone, and wireless media such as acoustic, RF, infrared, cellular,
and other wireless media. The term computer-readable media as used herein
includes both storage media and communication media. The processor 1158
also can have input device(s) 1176 such as keyboard, keypad, mouse, pen,
voice input device, touch input device, etc. Output device(s) 1174 such
as a display, speakers, printer, etc. also can be included.

[0041]The network and nodes illustrated in FIGS. 1 may comprise any
appropriate telephony radio network, or any other type of communications
network, wireline or wireless, or any combination thereof The following
description sets forth some exemplary telephony radio networks, such as
the global system for mobile communications (GSM), and non-limiting
operating environments. The below-described operating environments should
be considered non-exhaustive, however, and thus the below-described
network architectures merely show how emergency call processing may be
implemented with stationary and non-stationary network structures and
architectures in order to provide emergency call services using
distributed nodes. It can be appreciated, however, that methods and
systems for providing emergency call services using distributed nodes
such as those described herein can be incorporated with existing and/or
future alternative architectures for communication networks as well.

[0042]The GSM is one of the most widely utilized wireless access systems
in today's fast growing communication environment. The GSM provides
circuit-switched data services to subscribers, such as mobile telephone
or computer users. The General Packet Radio Service (GPRS), which is an
extension to GSM technology, introduces packet switching to GSM networks.
The GPRS uses a packet-based wireless communication technology to
transfer high and low speed data and signaling in an efficient manner.
The GPRS attempts to optimize the use of network and radio resources,
thus enabling the cost effective and efficient use of GSM network
resources for packet mode applications.

[0043]As one of ordinary skill in the art can appreciate, the exemplary
GSM/GPRS environment and services described herein also can be extended
to 3G services, such as Universal Mobile Telephone System (UMTS),
Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD),
High Speed Packet Data Access (HSPDA), cdma2000 1× Evolution Data
Optimized (EVDO), Code Division Multiple Access-2000 (cdma2000 3×),
Time Division Synchronous Code Division Multiple Access (TD-SCDMA),
Wideband Code Division Multiple Access (WCDMA), Enhanced Data GSM
Environment (EDGE), International Mobile Telecommunications-2000
(IMT-2000), Digital Enhanced Cordless Telecommunications (DECT), 4G
Services such as Long Term Evolution (LTE), etc., as well as to other
network services that become available in time. In this regard, the
systems and methods for providing emergency call services using
distributed nodes can be applied independently of the method of data
transport, and do not depend on any particular network architecture, or
underlying protocols.

[0044]FIG. 5 depicts an overall block diagram of an exemplary packet-based
mobile cellular network environment, such as a GPRS network, in which the
systems and methods for providing emergency call services using
distributed nodes such as those described herein can be practiced. In an
example configuration, network 101 as illustrated in FIG. 1 may be
encompassed by or interact with the network environment depicted in FIG.
5. Similarly, central node 120 and alternate node 170 may communicate or
interact with a network environment such as that depicted in FIG. 5. In
such an environment, there may be a plurality of Base Station Subsystems
(BSS) 900 (only one is shown), each of which comprises a Base Station
Controller (BSC) 902 serving a plurality of Base Transceiver Stations
(BTS) such as BTSs 904, 906, and 908. BTSs 904, 906, 908, etc. are the
access points where users of packet-based mobile devices (e.g., wireless
devices 151 and 161) become connected to the wireless network. In
exemplary fashion, the packet traffic originating from user devices
(e.g., wireless devices 151 and 161) may be transported via an
over-the-air interface to a BTS 908, and from the BTS 908 to the BSC 902.
Base station subsystems, such as BSS 900, may be a part of internal frame
relay network 910 that can include Service GPRS Support Nodes (SGSN) such
as SGSN 912 and 914. Each SGSN may be connected to an internal packet
network 920 through which a SGSN 912, 914, etc. may route data packets to
and from a plurality of gateway GPRS support nodes (GGSN) 922, 924, 926,
etc. As illustrated, SGSN 914 and GGSNs 922, 924, and 926 may be part of
internal packet network 920. Gateway GPRS serving nodes 922, 924 and 926
may provide an interface to external Internet Protocol (IP) networks,
such as Public Land Mobile Network (PLMN) 950, corporate intranets 940,
or Fixed-End System (FES) or the public Internet 930. As illustrated,
subscriber corporate network 940 may be connected to GGSN 924 via
firewall 932, and PLMN 950 may be connected to GGSN 924 via border
gateway router 934. The Remote Authentication Dial-In User Service
(RADIUS) server 942 may be used for caller authentication when a user of
a mobile cellular device calls corporate network 940.

[0045]Generally, there can be four different cell sizes in a GSM network,
referred to as macro, micro, pico, and umbrella cells. The coverage area
of each cell is different in different environments. Macro cells may be
regarded as cells in which the base station antenna is installed in a
mast or a building above average roof top level. Micro cells are cells
whose antenna height is under average roof top level. Micro-cells may be
typically used in urban areas. Pico cells are small cells having a
diameter of a few dozen meters. Pico cells may be used mainly indoors. On
the other hand, umbrella cells may be used to cover shadowed regions of
smaller cells and fill in gaps in coverage between those cells.

[0047]A mobile switching center may be connected to a large number of base
station controllers. At MSC 1071, for instance, depending on the type of
traffic, the traffic may be separated in that voice may be sent to Public
Switched Telephone Network (PSTN) 1082 through Gateway MSC (GMSC) 1073,
and/or data may be sent to SGSN 1076, which then sends the data traffic
to GGSN 1078 for further forwarding.

[0048]When MSC 1071 receives call traffic, for example, from BSC 1066, it
may send a query to a database hosted by SCP 1072. The SCP 1072 may
process the request and may issue a response to MSC 1071 so that it may
continue call processing as appropriate.

[0049]The HLR 1074 may be a centralized database for users to register to
the GPRS network. HLR 1074 may store static information about the
subscribers such as the International Mobile Subscriber Identity (IMSI),
subscribed services, and a key for authenticating the subscriber. HLR
1074 may also store dynamic subscriber information such as the current
location of the mobile subscriber. HLR 1074 may also serve to intercept
and determine the validity of destination numbers in messages sent from a
device, such as mobile subscriber 1055, as described herein. Associated
with HLR 1074 may be AuC 1075. AuC 1075 may be a database that contains
the algorithms for authenticating subscribers and may include the
associated keys for encryption to safeguard the user input for
authentication.

[0050]In the following, depending on context, the term "mobile subscriber"
sometimes refers to the end user and sometimes to the actual portable
device, such as wireless device 151 or 161, used by an end user of a
mobile cellular service or a wireless provider. When a mobile subscriber
turns on his or her mobile device, the mobile device may go through an
attach process by which the mobile device attaches to an SGSN of the GPRS
network. In FIG. 6, when mobile subscriber 1055 initiates the attach
process by turning on the network capabilities of the mobile device, an
attach request may be sent by mobile subscriber 1055 to SGSN 1076. The
SGSN 1076 queries another SGSN, to which mobile subscriber 1055 was
attached before, for the identity of mobile subscriber 1055. Upon
receiving the identity of mobile subscriber 1055 from the other SGSN,
SGSN 1076 may request more information from mobile subscriber 1055. This
information may be used to authenticate mobile subscriber 1055 to SGSN
1076 by HLR 1074. Once verified, SGSN 1076 sends a location update to HLR
1074 indicating the change of location to a new SGSN, in this case SGSN
1076. HLR 1074 may notify the old SGSN, to which mobile subscriber 1055
was attached before, to cancel the location process for mobile subscriber
1055. HLR 1074 may then notify SGSN 1076 that the location update has
been performed. At this time, SGSN 1076 sends an Attach Accept message to
mobile subscriber 1055, which in turn sends an Attach Complete message to
SGSN 1076.

[0051]After attaching itself with the network, mobile subscriber 1055 may
then go through the authentication process. In the authentication
process, SGSN 1076 may send the authentication information to HLR 1074,
which may send information back to SGSN 1076 based on the user profile
that was part of the user's initial setup. The SGSN 1076 may then send a
request for authentication and ciphering to mobile subscriber 1055. The
mobile subscriber 1055 may use an algorithm to send the user
identification (ID) and password to SGSN 1076. The SGSN 1076 may use the
same algorithm and compares the result. If a match occurs, SGSN 1076
authenticates mobile subscriber 1055.

[0052]Next, the mobile subscriber 1055 may establish a user session with
the destination network, corporate network 1089, by going through a
Packet Data Protocol (PDP) activation process. Briefly, in the process,
mobile subscriber 1055 may request access to the Access Point Name (APN),
for example, UPS.com, and SGSN 1076 may receive the activation request
from mobile subscriber 1055. SGSN 1076 may then initiate a Domain Name
Service (DNS) query to learn which GGSN node has access to the UPS.com
APN. The DNS query may be sent to the DNS server within the core network
1070, such as DNS 1077, which may be provisioned to map to one or more
GGSN nodes in the core network 1070. Based on the APN, the mapped GGSN
1078 can access the requested corporate network 1089. The SGSN 1076 may
then send to GGSN 1078 a Create Packet Data Protocol (PDP) Context
Request message that contains necessary information. The GGSN 1078 may
send a Create PDP Context Response message to SGSN 1076, which may then
send an Activate PDP Context Accept message to mobile subscriber 1055.

[0053]Once activated, data packets of the call made by mobile subscriber
1055 may then go through radio access network 1060, core network 1070,
and interconnect network 1080, in a particular fixed-end system, or
Internet 1084 and firewall 1088, to reach corporate network 1089.

[0054]Thus, network elements that can invoke the functionality of
providing emergency call services using distributed nodes such as those
described herein can include but are not limited to Gateway GPRS Support
Node tables, Fixed End System router tables, firewall systems, VPN
tunnels, and any number of other network elements as required by the
particular digital network.

[0055]FIG. 7 illustrates another exemplary block diagram view of a
GSM/GPRS/IP multimedia network architecture 1100 in which the systems and
methods for providing emergency call services using distributed nodes
such as those described herein can be incorporated. As illustrated,
architecture 1100 of FIG. 7 includes a GSM core network 1101, a GPRS
network 1130 and an IP multimedia network 1138. The GSM core network 1101
includes a Mobile Station (MS) 1102, at least one Base Transceiver
Station (BTS) 1104 and a Base Station Controller (BSC) 1106. The MS 1102
is physical equipment or Mobile Equipment (ME), such as a mobile
telephone or a laptop computer (e.g., wireless devices 151 and 161) that
is used by mobile subscribers, in one embodiment with a Subscriber
identity Module (SIM). The SIM includes an International Mobile
Subscriber Identity (IMSI), which is a unique identifier of a subscriber.
The BTS 1104 may be physical equipment, such as a radio tower, that
enables a radio interface to communicate with the MS. Each BTS may serve
more than one MS. The BSC 1106 may manage radio resources, including the
BTS. The BSC may be connected to several BTSs. The BSC and BTS
components, in combination, are generally referred to as a base station
(BSS) or radio access network (RAN) 1103.

[0056]The GSM core network 1101 may also include a Mobile Switching Center
(MSC) 1108, a Gateway Mobile Switching Center (GMSC) 1110, a Home
Location Register (HLR) 1112, Visitor Location Register (VLR) 1114, an
Authentication Center (AuC) 1118, and an Equipment Identity Register
(EIR) 1116. The MSC 1108 may perform a switching function for the
network. The MSC may also perform other functions, such as registration,
authentication, location updating, handovers, and call routing. The GMSC
1110 may provide a gateway between the GSM network and other networks,
such as an Integrated Services Digital Network (ISDN) or Public Switched
Telephone Networks (PSTNs) 1120. Thus, the GMSC 1110 provides
interworking functionality with external networks.

[0057]The HLR 1112 is a database that may contain administrative
information regarding each subscriber registered in a corresponding GSM
network. The HLR 1112 may also contain the current location of each MS.
The VLR 1114 may be a database that contains selected administrative
information from the HLR 1112. The VLR may contain information necessary
for call control and provision of subscribed services for each MS
currently located in a geographical area controlled by the VLR. The HLR
1112 and the VLR 1114, together with the MSC 1108, may provide the call
routing and roaming capabilities of GSM. The AuC 1116 may provide the
parameters needed for authentication and encryption functions. Such
parameters allow verification of a subscriber's identity. The EIR 1118
may store security-sensitive information about the mobile equipment.

[0058]A Short Message Service Center (SMSC) 1109 allows one-to-one short
message service (SMS), or multimedia message service (MMS), messages to
be sent to/from the MS 1102. A Push Proxy Gateway (PPG) 1111 is used to
"push" (i.e., send without a synchronous request) content to the MS 1102.
The PPG 1111 acts as a proxy between wired and wireless networks to
facilitate pushing of data to the MS 1102. A Short Message Peer to Peer
(SMPP) protocol router 1113 may be provided to convert SMS-based SMPP
messages to cell broadcast messages. SMPP is a protocol for exchanging
SMS messages between SMS peer entities such as short message service
centers. The SMPP protocol is often used to allow third parties, e.g.,
content suppliers such as news organizations, to submit bulk messages.

[0059]To gain access to GSM services, such as voice, data, short message
service (SMS), and multimedia message service (MMS), the MS may first
register with the network to indicate its current location by performing
a location update and IMSI attach procedure. MS 1102 may send a location
update including its current location information to the MSC/VLR, via BTS
1104 and BSC 1106. The location information may then be sent to the MS's
HLR. The HLR may be updated with the location information received from
the MSC/VLR. The location update may also be performed when the MS moves
to a new location area. Typically, the location update may be
periodically performed to update the database as location updating events
occur.

[0060]GPRS network 1130 may be logically implemented on the GSM core
network architecture by introducing two packet-switching network nodes, a
serving GPRS support node (SGSN) 1132, a cell broadcast and a Gateway
GPRS support node (GGSN) 1134. The SGSN 1132 may be at the same
hierarchical level as the MSC 1108 in the GSM network. The SGSN may
control the connection between the GPRS network and the MS 1102. The SGSN
may also keep track of individual MS's locations and security functions
and access controls.

[0061]Cell Broadcast Center (CBC) 1133 may communicate cell broadcast
messages that are typically delivered to multiple users in a specified
area. Cell Broadcast is one-to-many geographically focused service. It
enables messages to be communicated to multiple mobile telephone
customers who are located within a given part of its network coverage
area at the time the message is broadcast.

[0062]GGSN 1134 may provide a gateway between the GPRS network and a
public packet network (PDN) or other IP networks 1136. That is, the GGSN
may provide interworking functionality with external networks, and set up
a logical link to the MS through the SGSN. When packet-switched data
leaves the GPRS network, it may be transferred to an external TCP-IP
network 1136, such as an X.25 network or the Internet. In order to access
GPRS services, the MS first attaches itself to the GPRS network by
performing an attach procedure. The MS then activates a packet data
protocol (PDP) context, thus activating a packet communication session
between the MS, the SGSN, and the GGSN.

[0063]In a GSM/GPRS network, GPRS services and GSM services may be used in
parallel. The MS may operate in one three classes: class A, class B, and
class C. A class A MS may attach to the network for both GPRS services
and GSM services simultaneously. A class A MS may also support
simultaneous operation of GPRS services and GSM services. For example,
class A mobiles may receive GSM voice/data/SMS calls and GPRS data calls
at the same time.

[0064]A class B MS may attach to the network for both GPRS services and
GSM services simultaneously. However, a class B MS does not support
simultaneous operation of the GPRS services and GSM services. That is, a
class B MS can only use one of the two services at a given time.

[0065]A class C MS can attach for only one of the GPRS services and GSM
services at a time. Simultaneous attachment and operation of GPRS
services and GSM services is not possible with a class C MS.

[0066]GPRS network 1130 may be designed to operate in three network
operation modes (NOM1, NOM2 and NOM3). A network operation mode of a GPRS
network may be indicated by a parameter in system information messages
transmitted within a cell. The system information messages may direct a
MS where to listen for paging messages and how to signal towards the
network. The network operation mode represents the capabilities of the
GPRS network. In a NOM1 network, a MS can receive pages from a circuit
switched domain (voice call) when engaged in a data call. The MS can
suspend the data call or take both simultaneously, depending on the
ability of the MS. In a NOM2 network, a MS may not receive pages from a
circuit switched domain when engaged in a data call, since the MS is
receiving data and is not listening to a paging channel. In a NOM3
network, a MS can monitor pages for a circuit switched network while
receiving data and vice versa.

[0067]The IP multimedia network 1138 was introduced with 3GPP Release 5,
and may include IP multimedia subsystem (IMS) 1140 to provide rich
multimedia services to end users. A representative set of the network
entities within IMS 1140 are a call/session control function (CSCF), a
media gateway control function (MGCF) 1146, a media gateway (MGW) 1148,
and a master subscriber database, called a home subscriber server (HSS)
1150. HSS 1150 may be common to GSM core network 1101, GPRS network 1130
as well as IP multimedia network 1138.

[0068]IP multimedia system 1140 may be built around the call/session
control function, of which there are three types: an interrogating CSCF
(I-CSCF) 1143, a proxy CSCF (P-CSCF) 1142, and a serving CSCF (S-CSCF)
1144. The P-CSCF 1142 is the MS's first point of contact with the IMS
1140. The P-CSCF 1142 may forward session initiation protocol (SIP)
messages received from the MS to an SIP server in a home network (and
vice versa) of the MS. The P-CSCF 1142 may also modify an outgoing
request according to a set of rules defined by the network operator (for
example, address analysis and potential modification).

[0069]I-CSCF 1143 forms an entrance to a home network and hides the inner
topology of the home network from other networks and provides flexibility
for selecting an S-CSCF. I-CSCF 1143 may contact subscriber location
function (SLF) 1145 to determine which HSS 1150 to use for the particular
subscriber, if multiple HSSs 1150 are present. S-CSCF 1144 may perform
the session control services for MS 1102. This includes routing
originating sessions to external networks and routing terminating
sessions to visited networks. S-CSCF 1144 may also decide whether an
application server (AS) 1152 is required to receive information on an
incoming SIP session request to ensure appropriate service handling. This
decision is based on information received from HSS 1150 (or other
sources, such as application server 1152). AS 1152 may also communicate
to location server 1156 (e.g., a Gateway Mobile Location Center (GMLC))
that provides a position (e.g., latitude/longitude coordinates) of MS
1102.

[0070]HSS 1150 may contain a subscriber profile and keep track of which
core network node is currently handling the subscriber. It may also
support subscriber authentication and authorization functions (AAA). In
networks with more than one HSS 1150, a subscriber location function
provides information on the HSS 1150 that contains the profile of a given
subscriber.

[0071]MGCF 1146 may provide interworking functionality between SIP session
control signaling from the IMS 1140 and ISUP/BICC call control signaling
from the external GSTN networks (not shown.) It may also control the
media gateway (MGW) 1148 that provides user-plane interworking
functionality (e.g., converting between AMR- and PCM-coded voice.) MGW
1148 may also communicate with other IP multimedia networks 1154.

[0072]Push to Talk over Cellular (PoC) capable mobile telephones may
register with the wireless network when the telephones are in a
predefined area (e.g., job site, etc.) When the mobile telephones leave
the area, they may register with the network in their new location as
being outside the predefined area. This registration, however, does not
indicate the actual physical location of the mobile telephones outside
the pre-defined area.

[0073]While example embodiments of systems and methods for providing
emergency call services using distributed nodes such as those described
herein have been described in connection with various communications
devices and computing devices/processors, the underlying concepts can be
applied to any communications or computing device, processor, or system
capable of implementing the distributed node systems and methods
described. The various techniques described herein can be implemented in
connection with hardware or software or, where appropriate, with a
combination of both. Thus, the methods and apparatuses for providing
emergency call services using distributed nodes, or certain aspects or
portions thereof, can take the form of program code (i.e., instructions)
embodied in tangible media, such as floppy diskettes, CD-ROMs, hard
drives, or any other machine-readable storage medium, wherein, when the
program code is loaded into and executed by a machine, such as a
computer, the machine becomes an apparatus for providing emergency call
services. In the case of program code execution on programmable
computers, the computing device will generally include a processor, a
storage medium readable by the processor (including volatile and
non-volatile memory and/or storage elements), at least one input device,
and at least one output device. The program(s) can be implemented in
assembly or machine language, if desired. The language can be a compiled
or interpreted language, and combined with hardware implementations.

[0074]The methods and systems for providing emergency call services using
distributed nodes as described herein can also be practiced via
communications embodied in the form of program code that is transmitted
over some transmission medium, such as over electrical wiring or cabling,
through fiber optics, or via any other form of transmission, wherein,
when the program code is received and loaded into and executed by a
machine, such as an EPROM, a gate array, a programmable logic device
(PLD), a client computer, or the like, the machine becomes an apparatus
for providing emergency call services using distributed nodes. When
implemented on a general-purpose processor, the program code combines
with the processor to provide a unique apparatus that operates to invoke
the functionality of a distributed node and/or emergency call system.
Additionally, any storage techniques used in connection with a
distributed node system can invariably be a combination of hardware and
software.

[0075]While emergency call services using distributed nodes has been
described in connection with the various embodiments of the various
figures, it is to be understood that other similar embodiments can be
used or modifications and additions can be made to the described
embodiment for performing the same function of providing emergency call
services using distributed nodes without deviating therefrom. For
example, one skilled in the art will recognize that providing emergency
call services using distributed nodes as described in the present
application may apply to any environment, whether wired or wireless, and
may be applied to any number of such devices connected via a
communications network and interacting across the network. Therefore,
providing emergency call services using distributed nodes should not be
limited to any single embodiment, but rather should be construed in
breadth and scope in accordance with the appended claims.